POS0665 INCIDENCE RATE AND FACTORS ASSOCIATED WITH FRACTURES AMONG ADULTS WITH ANKYLOSING SPONDYLITIS IN THE UNITED STATES
Authors: R. Stovall, E. Kersey, J. LI, R. Baker, C. Anastasiou, A. Palmowski, G. Schmajuk, L. S. Gensler, J. Yazdany
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Adults with ankylosing spondylitis (AS), also known as radiographic axial spondyloarthritis, are at a significantly increased risk of fracture relative to the general population. While some studies have evaluated the risk of fracture in AS, we do not have European or U.S. population-level studies assessing different fracture types performed within the last three decades. <h3>Objectives</h3> We evaluated the incidence rate and factors associated with fractures among those with AS using linked data from the national U.S. Rheumatology Informatics System for Effectiveness (RISE) registry and Medicare claims. <h3>Methods</h3> Data were derived from RISE, a large, national electronic health record-based registry, which was linked to Medicare claims from 2016-2018. Patients were required to have at least two visits for AS with a rheumatology provider, ≥ 30 days apart, prior to the baseline period of the study and at least one Medicare claim. One year of baseline characteristics was collected from both RISE and Medicare claims. Subjects were considered to have a historical fracture (vs. an incident fracture) if a fracture occurred prior to the index date. Patients were followed over time for incident fractures after the index date. Fractures were defined by ICD codes. We examined all fractures, including those of the vertebrae, sternum/ribs, shoulder/clavicle/upper arm/elbow, distal forearm/wrist/hand, pelvis/hip/femur, knee/lower leg, and ankle/foot. First, we calculated the combined incidence of fracture and incidence by fracture type. Second, logistic regression models were constructed to identify factors associated with fracture, including age, sex, race or ethnic group, national area deprivation index, dual-eligibility for Medicare (healthcare for adults aged 65+ and some people with certain conditions/disabilities) and Medicaid (healthcare for those with limited income and resources), Charlson comorbidity index, body mass index, smoking status, osteoporosis diagnosis, historical fracture (fracture prior to index date), and use of glucocorticoids and opioids. <h3>Results</h3> We identified 1,426 adults with AS in RISE who were also observable in Medicare. The mean (SD) age was 69.4 years (9.8), 44.3% were female, and 77.3% were non-Hispanic White. Fractures occurred in 197 AS adults (<b>Table 1</b>). The overall incidence rate of fractures among adults with AS was 76.7 (95% CI 66.4-88.6) per 1,000 person-years. The most common fracture was vertebral with an incidence rate of 23.9 per 1,000 person-years (95% CI 18.6-30.7), followed by distal forearm/wrist/hand with an incidence rate of 17.4 per 1,000 person-years (95% CI 13.0-23.4). Age 85+ (OR 3.64, 95% CI 1.79-7.40), historical fracture (OR 5.18, 95% CI 3.40-7.89), and use of opioid drugs (OR 2.20, 95% CI 1.52-3.19) conferred increased odds of fracture; sex did not (<b>Figure 1</b>). <h3>Conclusion</h3> In this large U.S. sample of older adults with AS, vertebral fractures were the most common followed by distal forearm/wrist/hand fractures. Those who were older, had a historical fracture and used opioids had higher odds of fracture. Men and women were equally likely to have a fracture. Since chronic opioid use was associated with fracture in AS, this high-risk population should be considered for interventions to mitigate risk. Model adjusted for all variables shown in the Figure 1. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Rachael Stovall: None declared, Emma Kersey: None declared, Jing Li: None declared, Rahaf Baker: None declared, Christine Anastasiou: None declared, Andriko Palmowski: None declared, Gabriela Schmajuk: None declared, Lianne S. Gensler Consultant of: AbbVie, Acelyrin, Eli Lilly, Fresenius Kabi, Janssen, Novartis, Pfizer, and UCB Pharma, Grant/research support from: Novartis and UCB Pharma, Jinoos Yazdany Consultant of: Astra Zeneca, Pfizer, Aurinia, Grant/research support from: Astra Zeneca, BMS Foundation, Gilead and Aurinia.